Shower Cake Flavor/size???? Please Help

I'm making a bridal shower cake for this Sat and am in need of flavor/tier ideas. It's a beach theme for about 70ppl so I was planning on doing a 3tier(either 8-10-12 rounds or 8-10 rounds on top of 12sq or 11x15?? By looking at both the Wilton and Earlene chart it seems like this is more than enough cake but according to the servings at my local bakery it's not enough...very confused.

Also, they want a summery flavor. I wanted to do my strawberry cake but it is a sr cream cake and is very light and wouldn't hold up to stacking. Any suggestions/recipes on another option...lemon, lime?

Technically your support structure should be holding the top tier. The cake really shouldn't bear any of the weight. You may look into SPS if you want to use a more fragile cake for tiered cakes. It works great.